Vehicle Suspension

ABSTRACT

A bolster spring for a vehicle suspension including a base plate, a top plate, elastomeric material positioned between the base plate and the top plate, a first flange comprising a pair of ears having a bottom mounting surface upwardly extending from a first end of the base plate at an angle ½α, and one or more mounting holes positioned in the pair of ears in the first flange adapted for attachment to a pair of ears on an upwardly extending flange on a second bolster spring.

BACKGROUND

The present invention generally relates to vehicle suspensions. Moreparticularly, the present invention relates to vehicle suspensions usingbolster springs. Examples of vehicle suspensions having bolster springsare disclosed in U.S. Pat. No. 6,585,286 entitled “Vehicle Suspension”that issued on Jul. 1, 2003, herein incorporated by reference in itsentirety. This application also claims priority to U.S. patentapplication Ser. No. 29/574,562 filed on Aug. 16, 2016, the contents ofwhich are herein incorporated by reference in its entirety. The presentapplication includes improvements and advancements over the vehiclesuspensions disclosed in the '286 patent noted above.

SUMMARY

A vehicle suspension is provided having a frame attachment portionattached to a saddle, first and second bolster springs mounted to springmounts on an outboard side of the saddle and mounted on walls of aspring mount on an outboard side of an equalizing beam, and third andfourth bolster springs mounted to walls of a spring mount on an inboardside of the saddle and mounted to spring mounts on an inboard side ofthe equalizing beam. Upwardly extending flanges including a pair of earsis provided on the bottom of the first and second bolster springs thatare mounted to each other with common fasteners, and wherein upwardlyextending flanges on the bottom of the third and fourth bolster springsare mounted to each other with common fasteners. The mechanical jointsprovide retention integrity allowing for the use of fewer and smallerfasteners resulting in a lighter, more optimized design. In addition, anapex angle between the bolster springs has been reduced allowing them tooperate more in shear thereby providing for a decrease in the primaryand secondary suspension spring rates, as well as reduced axletranslation during braking and acceleration. In addition, the reducedapex angle and direct mounting of the bolster springs provides foradditional clearance for vehicle tires.

In one aspect, a bolster spring for a vehicle suspension is providedincluding a base plate, a top plate, elastomeric material positionedbetween the base plate and the top plate, a first flange comprising apair of ears having a bottom mounting surface upwardly extending from afirst end of the base plate at an angle ½α, and one or more mountingholes positioned in the pair of ears in the first flange adapted forattachment to a pair of ears on an upwardly extending flange on a secondbolster spring.

In another aspect, a bolster spring for a vehicle suspension is providedincluding a base plate, a top plate, elastomeric material positionedbetween the base plate and the top plate, a first flange having a bottommounting surface upwardly extending from a first end of the base plateat an angle ½α, and a tie-bar mounting flange rearwardly extending froman end of an intermediate plate positioned between the base plate andthe top plate.

In a further aspect, a suspension subassembly is provided including afirst bolster spring that comprises a base plate, a top plate,elastomeric material positioned between the base plate and the topplate, a first flange comprising a pair of ears having a bottom mountingsurface upwardly extending from a first end of the base plate at anangle ½α, one or more mounting holes positioned in the pair of ears inthe first flange adapted for attachment to a pair of ears on an upwardlyextending flange on a second bolster spring, the second bolster springincluding a base plate, a top plate, elastomeric material positionedbetween the base plate and the top plate, a first flange comprising apair of ears having a bottom mounting surface upwardly extending from afirst end of the base plate at an angle ½α, and one or more mountingholes positioned in the pair of ears in the first flange adapted forattachment to the pair of ears on the upwardly extending flange on thefirst bolster spring.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are described herein withreference to the drawings, wherein like parts are designated by likereference numerals, and wherein:

FIG. 1A is a perspective view of the outboard side of vehicle suspension50, according to an example embodiment;

FIG. 1B is a perspective view of vehicle suspension 50 shown in FIG. 1and oppositely disposed vehicle suspension 50;

FIG. 2 is a front view of the outboard side of vehicle suspension 50shown in FIGS. 1A and 1B;

FIG. 3 is a perspective view of the inboard side of vehicle suspension50 shown in FIGS. 1A, 1B, and 2;

FIG. 4 is a rear view of the inboard side of vehicle suspension 50 shownin FIGS. 2 and 3;

FIG. 5 is a bottom view of vehicle suspension 50 shown in FIGS. 1A-4;

FIG. 6 is a top view of vehicle suspension 50 shown in FIGS. 1A-5;

FIG. 7 is a right side view of vehicle suspension 50 shown in FIGS.1A-6;

FIG. 8 is a left side view of vehicle suspension 50 shown in FIGS. 1A-7;

FIG. 9 is a close up front view of vehicle suspension 50 showing bolstersprings 70 and 72, and load cushion 9;

FIG. 10 is a close up front perspective view of vehicle suspension 50shown in FIG. 9;

FIG. 11 is a perspective view of bolster spring 200, according to anexample embodiment;

FIG. 12 is a perspective bottom view of bolster spring 200 shown in FIG.11;

FIG. 13 is a left side view of bolster spring 200 shown in FIGS. 11 and12;

FIG. 14 is a right side view of bolster spring 200 shown in FIGS. 11-13;

FIG. 15 is a top view of bolster spring 200 shown in FIGS. 11-14;

FIG. 16A is a perspective top view of load cushion 300, according to anexample embodiment;

FIG. 16B is a perspective bottom view of load cushion 300 shown in FIG.16A;

FIG. 17 is a right side view of load cushion 300 shown in FIGS. 16A-16B;

FIG. 18 is front view load cushion 300 shown in FIGS. 16A-17;

FIG. 19 is a bottom view of load cushion 300 shown in FIGS. 16A-18;

FIG. 20 is a top view of load cushion 300 shown in FIGS. 16A-19;

FIG. 21A is a cross-sectional, perspective view of the inboard side ofvehicle suspension 50, taken along line 21A-21A in FIG. 4;

FIG. 21B is a cross-sectional, perspective view of the outboard ofvehicle suspension 50, taken along line 21B-21B in FIG. 2;

FIG. 22A is a cross-sectional, perspective view of the inboard side ofvehicle suspension 50, taken along line 22A-22A in FIG. 4;

FIG. 22B is a cross-sectional, perspective view of the outboard ofvehicle suspension 50, taken along line 22B-22B in FIG. 2;

FIG. 23A is a cross-sectional, perspective view of the inboard side ofvehicle suspension 50, taken along line 23A-23A in FIG. 4;

FIG. 23B is a cross-sectional, perspective view of the outboard ofvehicle suspension 50, taken along line 23B-23B in FIG. 2;

FIG. 24 is a perspective view of equalizing beam 100 of vehiclesuspension 50 shown in FIGS. 1A-10; according to an example embodiment;

FIG. 25 is a top view of equalizing beam 100 shown in FIG. 24;

FIG. 26 is a close up view showing how bolster springs 70 and 72 may bemounted to each other with a common fastener;

FIG. 27 is a perspective view of bolster spring 400;

FIG. 28 is a rear view of bolster spring 400;

FIG. 29 is a front view of bolster spring 400;

FIG. 30 is a right side view of bolster spring 400;

FIG. 31 is a left side view of bolster spring 400;

FIG. 32 is a top view of bolster spring 400;

FIG. 33 is a bottom view of bolster spring 400;

FIG. 34 is a bottom view of a suspension subassembly including bolstersprings 400 a and 400 b;

FIG. 35 is a perspective view of a suspension subassembly includingbolster springs 400 a and 400 b, shown in FIG. 34;

FIG. 36 is another perspective view of a suspension subassembly shown inFIGS. 34 and 35, including bolster springs 400 a and 400 b;

FIG. 37 is a perspective view of a suspension subassembly includingbolster springs 400 a and 400 b;

FIG. 38 is another perspective view of a suspension subassembly shown inFIG. 37; and

FIG. 39 is a perspective view of tie-bar 470 shown in FIGS. 37 and 38with fasteners 443 b′ and 441 b′.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A-10 provide various views of vehicle suspension 50. Vehiclesuspension 50 is designed to support longitudinally extending vehicleframe rails (not shown) which can be of various types that arepositioned above laterally extending vehicle axles. As will beappreciated by those skilled in the art, components of vehiclesuspension 50 are duplicated on each side of the vehicle as shown inFIG. 1B. It will also be appreciated that vehicle wheels may be mountedto the ends of the vehicle axles in a known manner. Further, it will beappreciated that the vehicle frame rails may be connected by one or morevehicle frame cross members.

Those skilled in the art will further understand that a suspension,arranged in accordance with the suspension 50 and the componentsthereof, alternatively may be attached to frame rails of a trailer (forexample, a trailer that connects to a semi-tractor). The frame rails ofa trailer may comprise frame rails such as those described above oranother type of frame rail.

For purposes of this description, unless specifically describedotherwise, hereinafter, “vehicle” refers to a vehicle or a trailer. Inthis way, for example, a vehicle frame refers to a vehicle frame or atrailer frame. Furthermore, for purposes of this description, the leftside of a vehicle refers to a side of the vehicle on an observer'sleft-hand side when the observer faces the back of the vehicle, and theright side of the vehicle refers to a side of the vehicle on anobserver's right-hand side when the observer faces the back of thevehicle. Furthermore still, for purposes of this description, “outboard”refers to a position further away from a center line, running from thefront to the back of a vehicle, relative to “inboard” which refers to aposition closer to that same center line.

FIG. 1A is a perspective view of an outboard side of vehicle suspension50 having a frame attachment portion 62 that is adapted for attachmentto a vehicle frame or frame rail with a plurality of mounting holes 63.Frame attachment portion 62 includes outer gussets 66 and 68 and centralflange 64 that provide additional strength and rigidity to the vehiclesuspension 50. Frame attachment portion 62 is attached to saddle 60.Bolster springs 70 and 72 are provided that each have a top attachedbolster spring mounts 170 and 172 extending from an outboard side ofsaddle 60 and a bottom attached to walls of bolster spring mount 107 bpositioned on equalizing beam 100. Equalizing beam 100 has a beam hub102 on a first end and a beam hub 104 on a second end. Beam hub 102includes a bar pin 110 adapted for attachment to a first axle (notshown) and beam hub 104 includes a bar pin 112 adapted for attachment toa second axle (not shown).

A pair of shock absorbers 120 and 122 each have one end mounted to theequalizing beam 100 and another end mounted to saddle 60 on the inboardside of vehicle suspension 50. In some applications, shock absorbers maynot be used. A load cushion 90 is mounted to load cushion mount 94extending from saddle 60 and load cushion 90 is positioned beneathsaddle 60 and positioned inwardly from and generally above bolstersprings 70 and 72. A first rebound strap 80 is mounted to load cushionmount 94, and a second rebound strap is mounted to load cushion mount 92(shown in FIG. 3). A bracket 191 having U-shaped ends that are used tomount rebound straps 80 may be positioned between the load cushion andthe load cushion mounts 92 and 94. In addition, shims of varyingthickness may positioned between the load cushion 90 and bracket 191 tochange the ride characteristics of the vehicle suspension 50.

FIG. 1B includes a second vehicle suspension 50 a that is a mirror imageof vehicle suspension 50, and may be positioned on an opposite side of avehicle frame. Accordingly, FIG. 1B provides a perspective view of theinboard side of vehicle suspension 50 a. Vehicle suspension 50 aincludes a frame attachment portion 62 a that is adapted for attachmentto a vehicle frame or frame rail with a plurality of mounting holes 63a. Frame attachment 62 a further includes outer gussets 66 a and 68 athat along with a central flange provide additional strength andrigidity to the vehicle suspension 50 a. Frame attachment portion 62 ais attached to saddle 60 a. Bolster springs 71 a and 73 a are providedthat each have a top attached to bolster spring spring mounts extendingfrom the inboard side of saddle 60 a and a bottom attached to bolsterspring mount 107 a positioned on equalizing beam 100 a. Equalizing beam100 a has a beam hub 102 a on a first end and a beam hub 104 a on asecond end. Beam hub 102 a includes a bar pin 110 a adapted forattachment to a second axle (not shown) and beam hub 104 a includes abar pin 112 a adapted for attachment to a first axle (not shown).

A pair of shock absorbers 120 a and 122 a each have one end mounted tothe inboard side of equalizing beam 100 a and another end mounted to theinboard side of saddle 60 a. A load cushion is mounted to load cushionmount 92 a extending from saddle 60 a. A rebound strap 80 a is mountedto load cushion mount 92 a.

FIG. 2 provides a front view of the outboard side of vehicle suspension50 and FIGS. 3 and 4 provide views of the inboard side of vehiclesuspension 50. In FIG. 2, load cushion 90 is shown mounted to loadcushion mount 94 extending from saddle 60. Bolster springs 70 and 72 aremounted to bolster springs mounts 170 and 172 outwardly extending fromoutboard wall 65 of saddle 60, and also to bolster spring mount 107 b onthe outboard side of the equalizing beam 100. As shown in FIG. 3,bolster springs 71 and 73 are mounted to bolster spring mounts 171 and173 extending from inboard wall 67 of saddle 60 and to walls of bolsterspring mount 107 a positioned on the inboard side of the equalizing beam100. The configuration of bolster springs 70-73 results in a balanced,split bolster spring arrangement where one pair of bolster springs 70and 72 is positioned on the outboard side of equalizing beam 100 and onepair of bolster springs 71 and 73 is positioned on the inboard side ofequalizing beam 100.

As shown in FIG. 3, shock absorber 120 has a first end secured to mount108 positioned on equaling beam 100 and a second end secured to mount 69positioned on saddle 60, and shock absorber 122 has a first end securedto mount 106 positioned on equalizing beam 100 and a second end securedto mount 13 positioned on saddle 60. In other embodiments, the secondends of shock absorbers 120 and 122 could also be mounted to a vehicleframe or frame rail, or not used at all.

Prior vehicle suspensions employing bolster springs typically providedan acute angle, or apex angle, between the bottoms of the bolstersprings of 53 degrees, which has become a de facto industry standard.However, as best shown in FIGS. 2 and 9, vehicle suspension 50significantly departs from the de facto apex angle standard of 53degrees. In particular, an apex angle α is provided that issignificantly less than 53 degrees. In the embodiments shown in FIGS.1-10, the apex angle α between the bottom of bolster springs 72 and 70(and the apex angle between bolster springs 71 and 73) is 37 degrees.While an apex angle of 37 degrees is preferred, the apex angle α mayrange between 34-40 degrees, or from 30-45 degrees, all lower than astandard apex angle of 53 degrees.

By reducing the apex angle α to 37 degrees, a number of importantadvantages are achieved. For example, the reduced apex angle α allowsthe springs to be positioned closer together, and thereby taking up lessspace longitudinally. In turn, a greater clearance between the vehicletires and the bolster spring arrangement is provided, which may providegreater tire chain clearance or allow for the use of larger tires. Inaddition, by reducing the apex angle α, the bolster springs are put moreinto a shear, rather than compression. As a result, a lower primaryvehicle spring rate may be achieved, while at the same time providingfor increased longitudinal stiffness. The present configuration of thebolster springs with an apex angle α of 37 degrees has increased thelongitudinal stiffness of the suspension resulting in a correspondingdecrease in the longitudinal deflection to less than an inch. As aresult, the reduced apex angle α has resulted in reduced axletranslation along the SAE X-Axis during braking and acceleration.

Reducing the apex angle α between the bolster springs has advantageouslyresulted in a reduction in the primary suspension spring rate to 1.5-2.0kN/mm depending upon the elastomer used to create the bolster springs.Furthermore, a secondary spring rate of the vehicle suspension when theload cushion is engaged measured at 1.0 g ranges from 2.0-3.5 kN/mmdepending upon the elastomers chosen for both the bolster springs andinitial gap between the load cushion and its reaction plate. Theseprimary and second vehicle suspension spring rates are orders ofmagnitude lower than traditional elastomeric suspensions and are on thesame order of magnitude as parabolic 6-rod suspensions.

Additionally, as discussed in more detail below with respect to FIG. 26,in addition to reducing the apex angle α between the bolster springs 70and 72, and 71 and 73, vehicle suspension 50 also incorporates a uniquebolster spring mounting arrangement wherein an angled flange 230 on thebottom plate 220 of bolster spring 70 is directly mounted to acorresponding angled flange 230 on bottom plate 220 of bolster spring 72using a pair of common fasteners for retention. Bolster springs 71 and73 are also directly mounted to each other using a pair of commonfasteners in the same manner. As used herein, the term “directlymounted” means that the flanges are mounted together using a commonfastener without a portion of the equalizing beam or bolster springmount positioned therebetween, although a gasket or spacer, or portionof a spring saddle, could be positioned therebetween and the flangeswould still be “directly mounted” to each other.

Directly mounting bolster springs 70 and 72 to each other, and directlymounting bolster springs 71 and 73 to each other using common fastenersprovides a number of advantages. In particular, the bolster springs maybe able to be positioned even closer together because there is noportion of the equalizing beam or a bolster spring mount extendingbetween the flanges of the bolster springs. Furthermore, using commonfasteners allows the positioning of the bolster springs to be closertogether than if independent fasteners were used for each bolsterspring. The closer positioning of the bolster springs allows evenfurther clearance from the tires, again providing even greater clearancefor tire chains or larger tires. The end result of directly mounting theflanges of the bolster springs with common fasteners provides for theuse of fewer fasteners, faster assembly, improved clearances tosurrounding components (because bolster springs are closer together), aswell as the creation of a mechanical joint between the mounted flangesof the bolster springs.

As known to those skilled in the art, a mechanical joint formed betweentwo components improves retention integrity and can permit the use ofsmaller fasteners compared to typical bolster spring designs. A benefitof smaller fasteners is improved clearances to surrounding packages, amore weight optimized design, and improved serviceability becausesmaller fasteners require less torque to achieve design load as apercent of proof load. Therefore, smaller fasteners are more easily andlikely to be tightened appropriately.

FIG. 5 is a bottom view of vehicle suspension 50. From this view, theequalizing beam 100 is shown with beam hub 104 having inboard side 104 aon one end with bar pin 112 and with beam hub 102 having inboard side102 a with bar pin 110. A center-plane 100 c of equalizing beam 100 isshown offset towards inboard side 104 a and inboard side 102 a adistance d from a center-plane of beam hubs 104 and 102. In thisembodiment, the center-plane is offset a distance d of 11 millimeters.Providing such an offset on the equalizing beam has the effect of movingthe vehicle suspension towards the inboard side of the vehicle frame,thereby advantageously providing additional clearance on the outboardside of the vehicle suspension.

In FIG. 5, there is a clear view of bolster spring 70 and bolster spring72 mounted to opposing walls of bolster spring mount 107 b extendingfrom an outboard side the vehicle suspension 50, as well as of bolsterspring 71 and bolster spring 73 mounted to opposing walls of bolsterspring mount 107 a extending from the inboard side of vehicle suspension50.

FIG. 6 shows a top view of vehicle suspension 50. In FIGS. 5 and 6,shock absorbers 120 and 122 can be seen secured to the inboard side ofsaddle using shock absorber mounts 106, 108, 13, and 69. In addition, agap 105 is shown on the surface of beam hubs 104 and 102 as a result ofthe offset d of center-plane 100 c. In FIG. 6, load cushion mount 94 isshown extending from an outboard side of saddle 60 and load cushionmount 92 is shown extending from an inboard side of saddle 60. Inaddition, central flange 64 is shown positioned on top surface 91 ofsaddle 60 attached to frame attachment portion 62.

FIG. 7 is a right side view of vehicle suspension 50 and FIG. 8 is aleft side view of vehicle suspension 50. Beam hub 102 is shown with barpin 110 adapted for attachment to a first axle (not shown) and beam hub104 is shown with bar pin 112 adapted for attachment for a second axle(not shown). Frame attachment portion 62 with gussets 68 and 66 areshown extending above outboard wall 65 and inboard wall 67 of the saddleand load cushion mount 94 is shown extending from the outboard side ofvehicle suspension 50. Shock absorber 122 is shown mounted to shockabsorber mount 13 and shock absorber 120 is shown mounted to shockabsorber mount 69. In addition, a pair of rebound straps 80 are shownextending from inboard and outboards sides of the vehicle suspension 50.Rebound straps 80 serve to prevent bolster springs 70-73 from beingoverstretched and overstressed when vehicle suspension 50 is placed inhang or rebound, such as when a vehicle is lifted with an outrigger,hits a large pothole, or during a sudden drop when going over a steepdrop in the road.

FIG. 9 is a close up front view of, and FIG. 10 is a close upperspective view of, the bolster springs 70 and 72 and load cushion 90on the outboard side of vehicle suspension 50. Bolster spring 70 isattached to bolster spring mount 170 on saddle 60 using fasteners 270 band 270 c, and also attached to bolster spring mount 107 a on theequalizing beam 100 using fastener 270 a. Similarly, bolster spring 72is attached to bolster spring mount 172 on saddle 60 using fasteners 272b and 272 c, and also attached to bolster spring mount 107 a on theequalizing beam 100 using fastener 272 a. As illustrated in FIG. 26,upwardly extending flange 230 of bolster spring 70 is directly mountedto a corresponding upwardly extending flange 230 of bolster spring 72using common fasteners, with a portion of spring saddle 193 positionedtherebetween. In other embodiments, the bolster springs flanges 230 maybe directly mounted to each other using common fasteners without aportion of a spring saddle positioned between them. As discussed above,apex angle α is formed between the bottom plates of bolster springs 70and 72.

To further strengthen the bolster spring assembly, a tie-bar 130 is usedto tie outboard bolster spring 70 to inboard bolster spring 71 (shown inFIG. 3 and FIG. 5) and tie-bar 132 is used to tie inboard bolster spring72 to inboard bolster spring 73 (shown in FIG. 3 and FIG. 5). In thisembodiment, the tie-bar is mounted in an intermediate plate located at amidpoint between the top plate and bottom plate of the bolster spring.The midpoint is the point most susceptible to buckling, bulging, orsplaying. Therefore, the tie-bar serves to react the inboard andoutboard bolster springs to prevent buckling or bulging at the mostvulnerable point on the bolster spring. The tie-bar therefore providesgreater rigidity and strength to the bolster spring assembly.

Furthermore, by directly mounting bolster spring 70 to bolster spring 72with common fasteners and directly mounting bolster spring 71 to bolsterspring 73 with common fasteners, and by connecting bolster spring 70 tobolster spring 71 using tie-bar 130 and by connecting bolster spring 72to bolster spring 73 using tie-bar 132, all four bolster springs 70, 71,72, and 73 are interconnected. As a result, the present embodimentsprovide a unified, interconnected assembly of bolster springs that ismore rigid and stable than if the bolster springs were not connected.

In addition, as shown in FIGS. 9 and 10, load cushion 90 is secured tooutboard load cushion mount 94 (and to inboard load cushion mount 92shown in FIG. 4), and is positioned above reaction plate 190. Reboundstrap 80 is attached to rebound strap flange 80 a and to rebound strapflange 80 b. The reaction plate 190 is secured via attachment to reboundstrap flange 80 b. In this embodiment, a bottom surface of the loadcushion 90 is positioned a distance D above the reaction plate 190.Distance D may preferably be 19 mm. Therefore, a primary spring rate isbased on the bolster springs, and when the load cushion 90 engages thereaction plate 190, a secondary spring rate that includes the loadcushion 90 is provided. In this embodiment, a hard stop has beenincluded at 68 mm of travel to protect the bolster springs and loadcushion from becoming overcompressed.

The hard stop feature is best shown in FIGS. 22A and 22B, wherefasteners 290 a used to mount the load cushion 90 downwardly extendtowards the reaction plate 190. Sleeves 291 are positioned around thefasteners 290 a and in this embodiment fasteners 290 a have a head 293extending from the end of sleeves 291. When load cushion 90 issignificantly compressed, e.g. at 50% compression, the heads 293 offasteners 290 a that contact the reaction plate 190 to provide a hardstop and prevent further compression of the load cushion 90. In otherembodiments, the bottom of sleeves 291 may be counterbored to enclosehead 293 so that the head 293 does not extend from the bottom of thesleeve 291 and instead the bottom of the sleeve 291 contacts thereaction plate 190 to provide the hard stop. The bottom of the sleeve291 has a greater surface area than head 293 of fasteners 290 a tospread the forces upon impact with the reaction plate 190. As a resultof the hard stop, there is a ceiling on the amount of strain that willexperienced by the bolster springs and load cushion. In this embodiment,the rebound strap 80 is comprised of woven material that isadvantageously removable to allow for easy repair or replacement of therebound strap 80. It should be noted that depending upon theapplication, the disclosed vehicle suspensions may be used without aload cushion.

The components of the vehicle suspension 50 shown in FIGS. 1-10 maycomprise cast or fabricated metal or composite material, including iron,steel, or aluminum. Frame attachment portion 62 and saddle 60, andequalizing beam 100 could also be cast with any suitable castablematerial. Similarly, the saddle 60 may comprise cast or fabricated metalor composite material. Depending on the application, the metal may, forexample, be nodular ductile iron (or more simply, ductile iron), steel,such as a high strength low alloy steel, or aluminum. Typically, highstrength low alloy steels are a preferred material to use for the framehanger and the saddle, although aluminum is often desired when weightconsiderations are of greater importance.

FIGS. 11-15 are views of a bolster spring 200. Bolster springs 70, 71,72, and 73 may be configured as bolster spring 200. As shown in FIGS.11-14, bolster spring 200 includes a base plate 220 and a top plate 210.Bolster spring 200 includes an elastomeric section 260 between baseplate 220 and intermediate plate 250, an elastomeric section 262 betweenintermediate plate 250 and intermediate plate 252, an elastomericsection 264 between intermediate plate 252 and intermediate plate 254,and an elastomeric section 266 between intermediate plate 254 and topplate 210. It should be noted that in other embodiments a greater orlesser number of intermediate plates can be used, including nointermediate plates.

Top plate 210 includes mounting holes 212 and 214 that are positioned onflanges of the top plate that extend beyond the elastomer zone withmounting hole 212 located on a flange on a first end of top plate 210and mounting hole 214 located on a flange on a second end of top plate210. Such a mounting hole arrangement allows for mounting to a bolsterspring mount without using studs extending from the elastomer zone.Bottom plate 220 includes mounting hole 222 that is positioned on aflange on a first end of bottom plate 220 that is also beyond theelastomer zone. An angled flange 230 extends from a second end of bottomplate 220. Angled flange 230 includes a pair of spaced mounting holes232 and 234 positioned beyond the elastomer zone that are adapted to bedirectly mounted to a corresponding angled flange of an adjacent bolsterspring, as illustrated in FIG. 26. Top plate 210 and bottom plate 220advantageously extend beyond the elastomer zone, and may be formedcomplementary in shape with the mounting surface of a bolster springmount to provide a larger mounting surface area, which forms a strongermechanical joint.

As shown in FIGS. 13 and 14, angled flange 230 may extend at an anglethat is one half of apex angle α, so that when directly mounted to theangled flange of an adjacent bolster spring having the sameconfiguration, an apex angle α is formed between the bottom surfaces ofthe directly connected bolster springs. In addition, a tie-bar mountingextension 240 having a through hole 241 through which a tie-bar mayextend is shown extending from center intermediate plate 252.

FIG. 15 is a top view of bolster spring 200. As can be seen, mountinghole 222 of the bottom plate 220 extends beyond the elastomer zone. Inaddition, mounting holes 232 and 234 on angled flange 230 extendoutwardly from the bottom plate 220 and have a spacing that is widerthan the width of the bottom plate 220 and the top plate 210. This widespacing of the mounting holes 232 and 234 on angled flange 230advantageously provides for greater contact between the angled flangesurfaces when mounted as shown in FIG. 26, resulting in a strongermechanical joint being formed between the angled flanges of the bolstersprings.

The particular configuration of the base plate 220, top plate 210, andintermediate plates 250, 252, and 254 of bolster spring 200 isillustrative only, and these components may have a variety of geometriesand configurations. Thus, the bolster spring 200 is not required tohave, but may have, the geometry shown in FIGS. 9-15. Furthermore, theuse of a tie-bar may be, but is not required to be, included.

A bolster spring is typically constructed from relatively flat first andsecond end plates with an elastomer connected between them. This springwill then have compressive and shear rates corresponding to the chosenmaterial, cross-section, and thickness of elastomer. In accordance withthe disclosed embodiments, bolster spring 200 may be constructed ofelastomeric sections 260, 262, 264, and 266 bonded to one or more ofplates 210, 250, 252, 254, and 220. Elastomeric sections 260, 262, 264,and 266 may comprise an elastomeric material (i.e., an elastomer) suchas natural rubber, synthetic rubber, styrene butadiene, syntheticpolyisoprene, butyl rubber, nitrile rubber, ethylene propylene rubber,polyacrylic rubber, high-density polyethylene, thermoplastic elastomer,a thermoplastic olefin (TPO), urethane, polyurethane, a thermoplasticpolyurethane (TPU), or some other type of elastomer. In this regard andin particular, elastomeric sections 260, 262, 264, and 266 may comprisean elastomer defined as American Society of Testing and Materials (ASTM)D2000 M4AA 717 A13 B13 C12 F17 K11 Z1 Z2. In this case, Z1 representsnatural rubber and Z2 represents a durometer selected to achieve adesired shear rate. The selected durometer may be based on a givenpredefined scale, such as the Shore A scale, the ASTM D2240 type Ascale, or the ASTM D2240 type D scale. In a preferred embodiment, inaccordance with the Shore A scale, Z2, for example, is preferably 70±5.In another embodiment, in accordance with the Shore A scale, Z2 is, forexample, within the range of 50 to 80. Other examples of Z2 and rangesfor Z2 are also possible.

In another respect, elastomeric sections 260, 262, 264, and 266 maycomprise a viscoelastomeric material that (i) has elasticcharacteristics when the bolster spring 200 is under a load within agiven range and when that load is removed, and (ii) has non-elasticcharacteristics (for example, does not return to an original non-loadedshape) if the applied load exceeds the greatest load of the given range.The given range may extend from no load to a maximum expected load plusa given threshold. The given threshold accounts for possible overloadingof bolster spring 200. As an example, the viscoelastomeric material maycomprise amorphous polymers, semi-crystalline polymers, and biopolymers.Other examples of the viscoelastomeric material are also possible.

In accordance with the example embodiments, elastomeric sections 260,262, 264, and 266 may also comprise one or more fillers. The filler(s)may optimize performance of elastomeric sections 260, 262, 264, and 266.The fillers may include, but are not limited to, wax, oil, curingagents, and/or carbon black. Such fillers may optimize performance byimproving durability and/or tuning the elastomeric sections for a givenshear load and/or a given compressive load applied to the elastomericsections. Improving durability through the use of fillers may include,for example, minimizing a temperature rise versus loading characteristicof the elastomeric sections and/or maximizing shape retention of theelastomeric sections.

Bolster spring 200 may be formed, for example, by inserting the plates210, 250, 252, 254, and 220 into a mold (not shown). The plates may eachbe coated with a coating material. As an example, the coating materialmay comprise a material comprising zinc and phosphate, modified withcalcium. The coating material may have a coating weight of 200-400milligrams per square foot. Other examples of the coating material arealso possible. A bonding agent may be applied to the coated plates forbonding the plates to the elastomeric sections. As an example, thebonding agent may comprise Chemlok® manufactured by the LordCorporation, Cary, N.C., USA. Other examples of the bonding agent arealso possible. Applying the coating material and/or applying the bondingagent may occur prior to, during, and/or after insertion of the platesinto the mold. After applying the coating material and the bondingagent, the elastomeric material (while in a pourable form) may beinserted into the mold to form the elastomeric sections.

In a preferred embodiment, any exposed portion of the plates (forexample, a portion of the plates not covered by the elastomericmaterial) is protected against corrosion by a means other than theelastomeric material. In other embodiments, some exposed portions of theplates (e.g., the edges of the plates) may not be protected againstcorrosion, whereas any other exposed portions of the plates areprotected against corrosion.

The plates 210, 250, 252, 254, and 220 can be made of any of a varietyof suitable materials, including, but not limited to, iron, steel,aluminum, plastic, a composite material, or some other material. Theplates may be fully, or at least substantially, encapsulated inelastomer to further enhance their corrosion resistance and friction atthe mating suspension members. As an example, plates 210, 250, 252, 254,and 220 can comprise plates having a thickness between a range of 0.188inches (3.00 mm) to 0.25 inches (6.35 mm), or more.

FIGS. 16A and 16B are perspective views of an example load cushion 300for use in vehicle suspension 50. FIG. 17 is a side view, FIG. 18 is afront view, FIG. 19 is a bottom view, and FIG. 20 is a top view of loadcushion 300. Load cushion 90 shown in vehicle suspension 50 in FIGS.1-10 may be arranged as load cushion 300.

As shown in one or more of FIGS. 16A-20, load cushion 300 includes a topplate 310, a bottom plate 320, and a load cushion portion 330. Top plate310 includes mounting flange 312 with mounting hole 312 a and mountingflange 314 with mounting hole 314 a adapted for mounting to load cushionmounts 92 and 94 (shown in FIGS. 2 and 4) of vehicle suspension 50. Inthis embodiment, a horizontal cross section of the cushion portion 330is generally square with rounded corners, although it could also begenerally circular, rectangular, or conic. As shown in FIGS. 16B and 19,the bottom plate 320 includes holes 322 that are used during the moldingprocess to provide a passage for the elastomeric material that forms thecushion portion 330.

As shown in FIG. 17, the load cushion portion 330 has a uniquesymmetrical shape that includes curvilinear front and rear outersurfaces 332 and 334 that taper towards the center at the midpointbetween the top plate 310 and bottom plate 320 such that the narrowestthickness of the load cushion 330 occurs at the midpoint. Similarly, asshown in FIG. 18, the load cushion portion 330 has a unique symmetricalshape that includes curvilinear left and right outer surfaces 336 and338 that taper towards the center at the midpoint between the top plate310 and bottom plate 320 such that the narrowest thickness of the loadcushion 330 occurs at the midpoint.

Load cushion 330 may have a cross section where front and rear outersurfaces 332 and 334 have a negative Gaussian curvature, and similarlyload cushion 330 may have a cross section where left and right outersurfaces 336 and 338 have a negative Gaussian curvature. In addition,load cushion portion 330 may be shaped as a hyperboloid. The curvedouter surfaces of the load cushion portion result in a much lowerelastomeric strain on the load cushion for the same deflection ascompared to a linearly reduced cross-section.

The load cushion 90 may undergo 50% compression at full jounce, or whenthe hard stop discussed above is reached. At this point, thecross-section of the load cushion portion 330 changes from a negativeGaussian curvature to a 0 or slightly positive Gaussian curvature. Asused herein the term, 0 Gaussian curvature means that the outer surfacesof the cross-section are parallel, and a “slightly positive Gaussiancurvature” means that the midpoint of the load cushion portion 330becomes wider than the end sections, by up to 1 cm on each side of theload cushion portion.

It will be appreciated that bottom plate 320 is not required, and theload cushion 330 may have an exposed surface instead of having bottomplate 320. The use of a bottom plate 320 does not affect in anysignificant way the load cushion load versus deflection curve. However,the bottom plate 320 may be incorporated to protect the active elastomerof the load cushion portion 330 from debris such as rocks that couldinadvertently end up on the reaction plate that is positioned beneaththe load cushion. Debris could become embedded temporarily orpermanently into the elastomer and create an undesirable crackinitiation site.

The bottom plate 320 may be encapsulated to provide for improvedcorrosion resistance, elimination of metal to metal contact resulting innoise reduction upon contact with the reaction plate, improved frictionbetween the load cushion 300 and the reaction plate 190 (shown in FIGS.9 and 10) to reduce or minimize wear between the bottom plate 320 andthe reaction plate 190 during vehicle motion because relative motion isdecreased or eliminated. In addition, encapsulation may be used as aservice wear and replacement indicator similar to wear bars foundbetween tire treads.

Load cushion 300 may have a continuously increasing spring rate as anapplied load increases and a continuously decreasing spring rate as anapplied load decreases, due to it generally conic shape.

The top plate 310 and base plate 320 may be constructed of any of avariety of suitable materials, including, but not limited to, iron,steel, aluminum, plastic, and a composite material. As an example, thebase plate can comprise a plate having a thickness between a range of0.188 inches (3.00 mm) to 0.25 inches (6.35 mm), or more. The plates canbe encapsulated in elastomer and/or bonded to the load cushion portionusing a bonding agent. The plate dimensions and shape can be varied toany dimension or shape desired for packaging, weight, and aesthetics.Preferably, the load cushion top plate 310 is dimensioned to (i) matchthe surface of the load cushion mount described herein, such as loadcushion mounts 92 and 94, (ii) locate mounting holes for securing theload cushion 300 to the load cushion mounts 92 and 94, and (iii)minimize overall mass.

The size and dimensions of the elastomer used for the cushion portion330 of load cushion 300 may be optimized for the vertical spring raterequirements. As noted above, the vertical spring rate for the loadcushions 300 may continuously increase with increasing load andcontinuously decreases with decreasing load, defining a curvilinearshape with no discontinuities on a graph illustrating spring rate as afunction of sprung load.

Preferably, load cushion portion 330 has a generally conic shape as itextends towards a midpoint between top plate 310 and bottom plate 320.With this preferred shape, the vertical spring rate for the load cushion300 linearly increases with increasing load and linearly decreases withdecreasing load. In this regard, load cushion 300 is operable as aprogressive spring rate load cushion. In one embodiment, the crosssection of load cushion portion 330 adjacent top plate 310 and adjacentbottom plate 320 is 110 mm by 110 mm. At the midpoint between the topplate 310 and the bottom plate 320 the load cushion portion 330 thecross section is 88 mm by 88 mm, and the height of load cushion portion330 is 105 mm not including plates or wear layer encapsulation. Otherexample dimensions of portions of load cushion 300 are also possible.For a given geometry, the spring rate of load cushion 300 may beoptimized by varying the durometer of the elastomer. By varying thedurometer, a family of interchangeable progressive spring rate loadcushions can be created.

It will further be appreciated that the load cushion 300 may be mountedwith the cushion portion 330 extending either above or below the bottomplate 310. Likewise, the load cushion 300 may be mounted such that thetop plate 310 extends beneath the bottom plate 320. Therefore, the useof the terms “top” and “bottom” are used simply to describe the plates310 and 320 that are attached to the load cushion portion 330, and donot in any way require that the load cushion 300 is mounted in anyparticular configuration.

FIG. 21A is a cross sectional inboard perspective view of vehiclesuspension 50 taken along line 21A-21A shown in FIG. 4, and FIG. 21B isa cross sectional inboard perspective view of vehicle suspension 50taken along line 21B-21B shown in FIG. 2. Frame attachment portion 62with mounting holes 63 is shown extending upwardly from upper surface 91of the saddle with central flange 64 and gusset 68. Shock absorber 122is shown mounted to inboard surface 67 of the saddle and rebound strap80 is shown extending beneath load cushion mount 92. Bolster springs 70and 71 are shown mounted to bolster spring mounts 170 and 171 onopposite sides of equalizing beam 100. Similarly, bolster springs 72 and73 are shown mounted to bolster springs mounts 172 and 173 on oppositesides of equalizing beam 100. In addition, common fastener 71 b is showndirectly mounting bolster spring 71 to bolster spring 73 and commonfastener 70 b is shown directly mounting bolster spring 70 to bolsterspring 72.

FIG. 22A is a cross sectional inboard perspective view of vehiclesuspension 50 taken along line 22A-22A shown in FIG. 4, and FIG. 22B isa cross sectional outboard perspective view of vehicle suspension 50taken along line 22B-22B shown in FIG. 2. Frame attachment portion 62with mounting holes 63 is shown extending upwardly from upper surface 91of the saddle with central flange 64 and gusset 68. Shock absorber 122is shown mounted to inboard surface 67 of the saddle and rebound straps80 are shown extending on opposite sides of load cushion 90. Loadcushion 90 can be seen positioned directly above reaction plate 190.Load cushion 90 is also shown mounted to the load cushion mountsextending from walls 65 and 67 of the saddle using fasteners 290 a.

Spring saddle 193 is shown supporting reaction plate 190. Throughhole 70d is positioned in reaction plate 190 to allow a fastener to extendtherethrough for mounting together the angled flanges of bolster springs70 and 72. Similarly, throughhole 71 d is positioned in reaction plate190 to allow a fastener to extend therethrough for mounting together theangled flanges of bolster springs 71 and 73.

In addition, equalizing beam 100 is shown having a U-shaped crosssection with opposed walls 100 a and 100 b. A tie-bolt 101 having asleeve 103 is used to tie the two walls 100 a and 100 b together.Tie-bolt 101 is used to relieve stress in the equalizing beam 100 wherethe bolster springs 70-73 are attached by “pinching” walls 100 a and 100b together such that their inner surfaces contact respective endsurfaces of sleeve 103.

FIG. 23A is a cross sectional inboard perspective view of vehiclesuspension 50 taken along line 23A-23A shown in FIG. 4, and FIG. 23B isan outboard perspective cross sectional view of vehicle suspension 50taken along line 23B-23B shown in FIG. 2. Frame attachment portion 62with mounting holes 63 is shown extending upwardly from upper surface 91of the saddle with central flange 64 and gusset 68. Shock absorber 122is shown mounted to inboard surface 67 of the saddle and rebound straps80 are shown extending on opposite sides of load cushion 90. Loadcushion 90 can be seen positioned directly above reaction plate 190.Load cushion 90 is also shown mounted to the load cushion mountsextending from walls 65 and 67 of the saddle.

FIG. 24 is a perspective view of the inboard side of equalizing beam 100and FIG. 25 is a top view of equalizing beam 100. Beam hubs 102 and 104are located on opposite ends of the equalizing beam 100. Shock absorbermount 106 having mounting hole 106 a and shock absorber mount 108 havingmounting hole 108 a are shown positioned on the inboard side of theequalizing beam 100. Bolster spring mounts 107 a and 107 b extend fromopposite sides of the center of equalizing beam 100. On the inboardside, the walls of bolster spring mount 107 a include mounting holes 109a and 109 b that are used to mount bolster springs 71 and 73 (shown inFIG. 3), and on the outboard side, the walls of bolster spring mount 107b include mounting holes 108 b and 108 a that are used to mount bolstersprings 70 and 72 (shown in FIG. 2).

The equalizing beam 100 is shown in an illustrative configuration.However, equalizing beam 100 may be constructed in any of a variety ofarrangements and with a variety of configurations and/or materials.

FIG. 26 provides an illustration showing how bolster springs 70 and 72may be directly mounted to each other using common fasteners. Inparticular, flanges 230 of bolster springs 70 and 72 are positionedtogether as shown, with spring saddle 193 extending therebetween,wherein a pair of common fasteners may be used to directly mount thebolster springs 70 and 72 together. Spring saddle 193 may be formed froma pair of bent plates having a thickness of 6 mm, such that the flanges230 are positioned 12 mm apart. In addition, apex angle α is shownbetween the bottom surfaces of bottom plates 220 of bolster springs 70and 72.

FIGS. 27-33 show various view of bolster spring 400, that may be used insuspension assembly 50 described above. Bolster spring 400 includes atop plate 410 having mounting apertures 412 and 414. Bolster spring 400also includes a bottom plate 420 having mounting aperture 422.Intermediate plates 450, 452, and 454 are positioned between top plate410. Elastomeric section 460 is positioned between bottom plate 420 andintermediate plate 450. Elastomeric section 462 is positioned betweenintermediate plate 450 and intermediate plate 452. Elastomeric section464 is positioned between intermediate plate 452 and intermediate plate454. Elastomeric section 466 is positioned between intermediate plate454 and top plate 410. Elastomeric sections 460, 462, 464, and 466 maybe constructed in the same manner and with the same materials asdescribed above with respect to bolster spring 200. In addition, topplate 410, bottom plate 420, and intermediate plates 450, 452, and 454may be constructed in the same manner and the same materials asdescribed above with respect to bolster spring 200.

Bottom plate 420 includes an extending section 430 from which upwardlyextending ears 436 and 438 extend at an angle. A gap 439 extends betweenears 436 and 438 to provide additional mounting clearance. Ear 436includes a mounting aperture 432 and ear 438 includes a mountingaperture 434. Ears 436 and 438 together constitute an upwardly extendingflange. Intermediate plate 452 advantageously includes a rearwardlyextending flange 440 that includes mounting apertures 444, 445, and 446that are adapted for attachment to a tie-bar.

FIG. 34 is a bottom view of a suspension subassembly including bolstersprings 400 a and 400 b. FIG. 35 is a perspective view of a suspensionsubassembly including bolster springs 400 a and 400 b, shown in FIG. 34.FIG. 36 is another perspective view of a suspension subassembly shown inFIGS. 34 and 35, including bolster springs 400 a and 400 b.

Bolster springs 400 a and 400 b are secured to each other with tie-bar470. In particular bolts 441 a and 443 a are used to secure tie-bar 470to rearwardly extending flange 440 a with nuts 445 a and 447 arespectively. Similarly, bolts 441 b and 443 b are used to securetie-bar 470 to rearwardly extending flange 440 b with nuts 445 b and 447b. Gap 439 between ears 436 and 438 (shown in FIG. 27) providesclearance for the bolts to connect with the rearwardly extending flange440 a and 440 b, respectively.

It will be appreciated that ears 436 and 438 of the suspensionsubassembly shown in FIGS. 34-36 may be secured to a correspondingsuspension subassembly with a common fastener in the same manner asshown in suspension 50 and bolster springs 200.

FIGS. 37-39 show alternate fasteners 443 b′ and 441 b′ that may be usedto secure tie-bar 470 to rearwardly extending mounting flange 440 b withnuts 447 b and 445 b, and also alternate fasteners 441 a′ and 443 a′that may be used to secure tie-bar 470 to rearwardly extending mountingflange 440 a with nuts 445 a and 445 b. Fasteners 443 b′, 441 b′, 441a′, and 443 a′ differ from fasteners 443 b, 441 b, 441 a, and 443 a inthat rather than have a nut-shaped head, fasteners 443 b′, 441 b′, 441a′, and 443 a′ have a round, low-profile head that is much thinner thanthe nut-shaped head of fasteners 443 b, 441 b, 441 a, and 443 a. As aresult, the low-profile head provides for additional clearance toprovide for wider articulation angles that may be experienced duringoperation of a vehicle. The term “low-profile” means that the head has athickness that is 50% or less than the thickness of a nut shaped head.For example the nut-shaped head on an M12 bolt has a thickness of 12 mm,whereas the low-profile head on an equivalent bolt may have a thicknessof 3-6 mm. The head of fasteners 443 b′, 441 b′, 441 a′, and 443 a′ isshown as round, although it could other shapes, such as square orhexagonal.

Although not required, fasteners 443 b′ and 441 b′ may have a stud thatis knurled and which may be advantageously press fit into correspondingholes in rearwardly extending mounting flange 440 b and a bottom of thelow profile head may be drawn into engagement with surfaces 474 and 472respectively of tie-bar 470 by tightening a nut onto a threaded end ofthe stud. Fasteners 441 a′ and 443 b′ may be configured in the samemanner and press fit into corresponding rearwardly extending mountingflange 440 a and drawn into engagement with surfaces of tie-bar 470 inthe same manner. In other applications, the fasteners 443 b′, 441 b′,441 a′, and 443 a′ may not have a knurled surface and may not be pressfit into the corresponding mounting holes of rearwardly extendingmounting flanges 440 b, and 440 a.

The current tie-bar setup shown in FIGS. 27-38, with its fastener(rearwardly extending flange 440) that bolts two rate plates together isgreat for articulation levels up to a certain degree. In high severityapplications, the bolster twists to the point where the curl plateitself (shown in bolster spring 200) starts to overcome the preload onthe bolt, put the bolt in bending, and stress up the curl plates towhere expensive material options would be the only fix (without affectedpackaging).

With the tie-bar forging with the rearwardly extending flange 440 shownin FIGS. 27-38, the bending stiffness can be tuned in multipledirections so that in severe applications the bar itself stresses up,keeps load out of the bolts, and allows the plates to rotate relative toone another (with the forging bending and/or twisting in between). Thisincreases integrity of the entire joint, as the 1 main bolt moves to 4separate bolts, distributing load, and the forging stresses up insteadof the rate plates.

This has the added benefit of keeping high strength steel rate platesout of the mold, which are harder to use in processing. The forgingdoesn't need to go in the mold and can be tuned (material andprocess/design wise) for different applications of the same bolster.

Example embodiments of the present invention have been described above.Those skilled in the art will understand that changes and modificationsmay be made to the described embodiments without departing from the truescope and spirit of the present invention, which is defined by theclaims.

We claim:
 1. A bolster spring for a vehicle suspension comprising: abase plate; a top plate; elastomeric material positioned between thebase plate and the top plate; a first flange comprising a pair of earshaving a bottom mounting surface upwardly extending from a first end ofthe base plate at an angle ½α; and one or more mounting holes positionedin the pair of ears in the first flange adapted for attachment to a pairof ears on an upwardly extending flange on a second bolster spring. 2.The bolster spring of claim 1, wherein a tie-bar mounting flangerearwardly extends from an end of an intermediate plate positionedbetween the base plate and the top plate.
 3. The bolster spring of claim1, wherein the angle ½α is between 15-22.5 degrees.
 4. The bolsterspring of claim 3, wherein the angle ½α is between 17.5-20 degrees. 5.The bolster spring of claim 4, wherein the angle ½α is 18.5 degrees. 6.The bolster spring of claim 1, wherein when the bottom surface of thepair of ears of the first flange of the bolster spring is positionedagainst a bottom surface of a pair of ears of a flange of a secondbolster spring constructed the same as the first bolster spring, an apexangle α of between 30-45 degrees is formed between a bottom surface ofthe first bolster spring and a bottom surface of the second bolsterspring.
 7. The bolster spring of claim 1, wherein the one or moremounting holes on the pair of ears on the first flange have a gappositioned therebetween.
 8. The bolster spring of claim 1, wherein theone or more mounting holes on the pair of ears are spaced apart, andwherein a distance between the one or more mounting holes on the pair ofears is greater than a width of the base plate.
 9. The bolster spring ofclaim 2, wherein the tie-bar mounting flange includes a plurality ofmounting holes adapted for attachment to a tie-bar.
 10. The bolsterspring of claim 9, wherein the tie-bar mounting flange includes threemounting holes adapted for attachment to the tie-bar.
 11. A bolsterspring for a vehicle suspension comprising: a base plate; a top plate;elastomeric material positioned between the base plate and the topplate; a first flange having a bottom mounting surface upwardlyextending from a first end of the base plate at an angle ½α; and atie-bar mounting flange rearwardly extending from an end of anintermediate plate positioned between the base plate and the top plate.12. The bolster spring of claim 11, wherein the tie-bar mounting flangeincludes a plurality of mounting holes adapted for attachment to atie-bar.
 13. The bolster spring of claim 12, wherein the tie-barmounting flange includes three mounting holes adapted for attachment tothe tie-bar.
 14. The bolster spring of claim 11, wherein the firstflange comprises a pair of ears, wherein one or more mounting holes arepositioned in the pair of ears in the first flange adapted forattachment to a pair of ears on an upwardly extending flange on a secondbolster spring.
 15. The bolster spring of claim 14, wherein the one ormore mounting holes on the pair of ears on the first flange have a gappositioned therebetween.
 16. The bolster spring of claim 14, wherein theone or more mounting holes on the pair of ears are spaced apart, andwherein a distance between the one or more mounting holes on the pair ofears is greater than a width of the base plate.
 17. A suspensionsubassembly comprising a first bolster spring that comprises: a baseplate; a top plate; elastomeric material positioned between the baseplate and the top plate; a first flange comprising a pair of ears havinga bottom mounting surface upwardly extending from a first end of thebase plate at an angle 1/2α; one or more mounting holes positioned inthe pair of ears in the first flange adapted for attachment to a pair ofears on an upwardly extending flange on a second bolster spring; thesecond bolster spring comprising: a base plate; a top plate; elastomericmaterial positioned between the base plate and the top plate; a firstflange comprising a pair of ears having a bottom mounting surfaceupwardly extending from a first end of the base plate at an angle ½α;and one or more mounting holes positioned in the pair of ears in thefirst flange adapted for attachment to the pair of ears on the upwardlyextending flange on the first bolster spring.
 18. The suspensionsubassembly of claim 17, wherein the first bolster spring includes atie-bar mounting flange rearwardly extending from an end of anintermediate plate positioned between the base plate and the top plate;wherein the second bolster spring includes a tie-bar mounting flangerearwardly extending from an end of an intermediate plate positionedbetween the base plate and the top plate; and wherein a tie-bar ismounted to the tie-bar mounting flange of the first bolster spring andto the tie-bar mounting flange of the second bolster spring to securethe first bolster spring to the second bolster spring.
 19. Thesuspension subassembly of claim 18, wherein the tie-bar is secured tothe tie-bar mounting flange of the first bolster spring with a firstplurality of bolts and the tie-bar is also secured to the tie-barmounting flange of the second bolster spring with a second plurality ofbolts.
 20. The suspension subassembly of claim 18, wherein the tie-baris secured to the tie-bar mounting flange of the first bolster springwith a first plurality of studs having a low-profile head and thetie-bar is also secured to the tie-bar mounting flange of the secondbolster spring with a second plurality of studs having a low-profilehead.
 21. The suspension subassembly of claim 20, wherein the firstplurality of studs have a knurled surface that is press fit into acorresponding first plurality of holes in the tie-bar mounting flange ofthe first bolster spring and the second plurality of studs have aknurled surface that is press fit into a corresponding second pluralityof holes in the tie-bar mounting flange of the second bolster spring.22. The suspension subassembly of claim 20, wherein the first pluralityof studs have a threaded end such that when a nut is torqued onto thethreaded end an inner surface of the low-profile head is brought intoengagement with the tie-bar; and wherein the second plurality of studshave a threaded end such that when a nut is torqued onto the threadedend an inner surface of the low-profile head is brought into engagementwith the tie-bar.